Ametrida centurio, J. E. Gray, 1847

Don E. Wilson & Russell A. Mittermeier, 2019, Phyllostomidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 444-583 : 583

216.

Little White-shouldered Bat

Ametrida centurio

French: Centurion amétride / German: Kleine Weil 3schulterfledermaus / Spanish: Ametrida de cara plana

Taxonomy. Ametrida centurio J. E. Gray, 1847 ,

“Brazils, Para.” Restricted by R. L. Peterson in 1965 to Belém, Para, Brazil.

Because male and female Ametrida centurio are very dimorphic, males had previously been described as a separated species, A. minor Peterson, 1965 , currently a junior synonym. Ametrida centurio is in the tribe Stenodermatini , which encompasses bat species with highly shortened rostra and anteriorly rounded palates not extending posteriorly and with pronounced secondary sexual dimorphism. Monotypic.

Distribution. Panama (Barro Colorado I), Venezuela, the Guianas, and Brazil (N Amazon Basin S to Serra do Roncador in Mato Grosso, and a single record from the Atlantic Forest in Paraiba); also on Bonaire and Trinidad Is.

Descriptive notes. Head-body 35-46 mm (males) and 40-53 mm (females), no tail, ear 11-15 mm (males) and 11:-5-15 mm (females), hindfoot 9 mm (males) and 8 mm (females), forearm 24-6-26-5 mm (males) and 29-8-33-2 mm (females); weight 7-8 8 g (males) and 10 g (females). The Little White-shouldered Bat is small and sexually dimorphic, with females much larger than males and with other different secondary sexual characteristics, such as more pronounced swollen periorbital region of males. Pelage is pale brown to dark rusty brown, with tricolored hairs having medium brown bases and tips and grayish middles. Ventral fur is unicolored and same color as dorsum, except paler on throat, neck, and upper part of chest. There is one pair of white spots on shoulders and another on lateral parts of neck—a condition shared by all stenodermatine bats. Wings are brownish, except for dactylopatagium minus that is broad and translucent, remaining permanently opened. Propatagium, dorsal uropatagium, and part of plagiopatagium are furry. Rostrum is very shortened and wide; region around muzzle and lips is virtually naked. Three wart-like papillae with vibrissae are located on each sides of horseshoe of noseleaf. Similar to horseshoe vibrissae, genal vibrissae arise from rounded, wart-like papillae. Lancet of noseleaf is broad and short. Eyes are olive and large. Periorbital region is more conspicuously swollen in males, probably associated with glands. Ears are broad at bases and pointed attips, and part of internal pinna surface is pale pinkish to yellowish. Forehead is roughly perpendicular in relation to palatal plane, braincase is rounded, and nasal boneis retracted, with distal tip shaped as a small rounded projection that can be seen in lateral and dorsal views. Facial process of maxilla appears dorso-ventrally compressed, and zygoma is overall much enlarged. Palate is wide and rounded. Dental formula is 12/2, C1/1,P 2/2, M 3/3 (x2) = 32. I' are small and triangular, with pointed main tips, and molars are expanded lateromedially, forming large crown surface. One specimen recently collected in Paraiba, north-eastern Atlantic Forest of Brazil, was unique compared with previously known specimens; it had one additional pair of white spots on venter, located mediolaterally on abdomen and semicircular white spot around (dorsal) to penis. Chromosomal complement has 2n = 30-31 and FN = 56. X-chromosome is subtelocentric, and Y-chromosome is metaor submetacentric. Karyotypes constitute aXx/X¥Y, system.

Habitat. Historically pristine Amazonian forests, isolated forested mountains surrounded by savanna ( Guyana) or “canga vegetation” (herbs and shrubs associated to iron-rich soils on top of mountains) in eastern Amazonia, open and forested habitats in western and central Amazonia, and recent records in forests associated to canga formations in south-eastern Amazonia and Atlantic Forest of north-eastern Brazil, mostly in lowlands but up to elevations over 2000 m.

Food and Feeding. The Little White-shouldered Bat is predominantly or exclusively frugivorous. Nevertheless, there is a report of it using flower products (nectar) of Parkia pendula ( Fabaceae ); bodies of seven females captured in central Amazonian Brazil were covered with pollen from this plant. Individuals have also been reported flying close to blossoming canopy Fabaceae in French Guiana. Feeding on nectar appear to be an opportunistic behavior because the Little White-shouldered Bat has no adaptations for nectar feeding and exhibits derived characters that might be related to highly specialized frugivory.

Breeding. Pregnant Little Whitesshouldered Bats have been captured in July-August on Trinidad Island and October in eastern Amazonia (Para). Lactating females have been recorded in July-August in Central Amazonia.

Activity patterns. The Little White-shouldered Bat is usually found in lowlands, evergreen forest near streams or moist areas, occasionally in clearings, secondary growth, or deciduous forests, adjacent to streams and river channels. It usually flies at canopy levels and has been captured in nets placed 8-34 m aboveground. A recent single record in Paraiba, north-eastern Brazil, was the first outside Amazonia and occurred in an intensively sampled area of fragmented Atlantic Forest; the individual was caught in a mist net 8: 3 m up in the canopy.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Little White-shouldered Bat is mostly rare in its area of occurrence, but it has been captured in higher numbers locally on some occasions.

Bibliography. Baker et al. (1979), Bernard (2002), Brosset & Charles-Dominique (1991), Carter et al. (1981), Gardner (2008f), Hsu et al. (1968), Lee & Dominguez (2000), Peterson (1965b), Rodriguez-Herrera & Hopkins (2000), Simmons & Voss (1998), Tavares (2008), Tavares et al. (2018), Vilar et al. (2015).

Figures

187. Brown Fruit-eating Bat (Artibeus concolor), 188. Honduran Fruit-eating Bat (Artibeus inopinatus), 189. Fraternal Fruit-eating Bat (Artibeus fraterculus), 190. Hairy Fruit-eating Bat (Artibeus hirsutus), 192. Ecuadorian Fruit-eating Bat (Artibeus aequatorialis), 193. Jamaican Fruit-eating Bat (Artibeus jamaicenss), 194. Dark Fruit-eating Bat (Artibeus obscurus), 195. Schwartz’s Fruit-eating Bat (Artibeus schwartzi), 196. Great Fruit-eating Bat (Artibeus lLituratus), 197. Large Fruit-eating Bat (Artibeus amplus), 198. Flat-faced Fruit-eating Bat (Artibeus planirostris), 199. Rosenberg’s Fruit-eating Bat (Artibeus rosenberg), 200. Thomas's Fruit-eating Bat (Artibeus watsoni), 201. Toltec Fruit-eating Bat (Artibeus toltecus), 202. Pygmy Fruit-eating Bat (Artibeus phaeotis), 203. Gervais’s Fruit-eating Bat (Artibeus cinereus), 204. Andersen’s Fruit-eating Bat (Artibeus anderseni), 205. Little Fruit-eating Bat (Artibeus ravus), 206. Aztec Fruit-eating Bat (Artibeus aztecus), 207. Bogota Fruit-eating Bat (Artibeus bogotensis), 208. Silvery Fruit-eating Bat (Artibeus glaucus), 209. Dwarf Fruit-eating Bat (Artibeus gnomus), 210. Jamaican Fig-eating Bat (Ariteus flavescens), 211. Tree Bat (Ardops nichollsi), 212. Red Fruit Bat (Stenoderma rufum), 213. Wrinkle-faced Bat (Centurio senex), 214. Ipanema Broad-nosed Bat (Pygoderma bilabiatum), 215. Visored Bat (Sphaeronycteris toxophyllum), 216. Little White-shouldered Bat (Ametrida centurio), 217. Cuban Fig-eating Bat (Phyllops falcatus)

Distribution. Panama (Barro Colorado I), Venezuela , the Guianas, and Brazil (N Amazon Basin S to Serra do Roncador in Mato Grosso, and a single record from the Atlantic Forest in Paraiba); also on Bonaire and Trinidad Is.